This invention relates to liquid-level detection for an enclosed tank or vessel, and more particularly to an apparatus that in some embodiments may be implemented without any moving parts and a method of using ambient light for visually detecting liquid-level either at or below a normal range in an enclosure tank.
Many enclosed devices depend for their proper functioning on the maintenance of a particular liquid-level within the enclosure tank or liquid vessel, and many systems have been developed for gauging such liquid-levels. Among such systems, however, few are well adapted for ultra-reliable performance in extremes of weather or for use on hazardous equipment such as medium voltage electrical switch gear and distribution equipment.
Many prior art devices have often been too complex for the degree of reliability required, or too expensive for practical application. Others have been susceptible to fouling by the certain types of liquid, such as transformer oil. Many, too, have been difficult to read or ambiguous in their indication. One particular prior art liquid-level gauge disclosed in U.S. Pat. No. 3,796,098 had features that people desired for their applications in gauging the liquid-level in an enclosure tank, but allowed potentially ambiguous scenarios such as due to residue, fowling, or the like.